Direct nanodroplet and microbubble comparison for high intensity focused ultrasound ablation enhancement and safety

Linsey Moyer,Paul Sheeran,Kelsie Timbie,Wilson Miller,Richard Price,Paul Dayton

doi:10.1186/2050-5736-3-s1-o67

Abstract

High intensity focused ultrasound (HIFU) surgery often requires hours of ablation in order to treat an entire tumor. Both perfluorocarbon gaseous microbubbles and vaporized liquid droplets are known enhancers of HIFU thermal ablation. Microbubbles, however, often lead to surface or skin lesions. Furthermore, they have a relatively short half-life in vivo (minutes) rendering them insufficiently stable for an entire HIFU surgery, which can last several hours. Many droplet formulations require very high pressures to activate. Our aim was to design an agent that could shorten ablation procedures without sacrificing safety. We designed and investigated a perfluorocarbon nanodroplet composed of a 1:1 ratio of dodecafluoropentane and decafluorobutane. These are tuned to change phase and activate at only 2 MPa peak negative pressure with common HIFU pulse lengths, enabling focused and targeted activation. Additionally, they are stable at body temperature.

Highlights

Background/introduction High intensity focused ultrasound (HIFU) surgery often requires hours of ablation in order to treat an entire tumor
HIFU-induced temperature rises were measured as a function of the time after the injection of the agent occurred and were compared to controls wherein no agent was injected
HIFU applied to livers without any agent induced only a 22 +/-3oC maximal temperature rise over body temperature

Summary

Introduction

Background/introduction High intensity focused ultrasound (HIFU) surgery often requires hours of ablation in order to treat an entire tumor. Both perfluorocarbon gaseous microbubbles and vaporized liquid droplets are known enhancers of HIFU thermal ablation. Microbubbles, often lead to surface or skin lesions They have a relatively short half-life in vivo (minutes) rendering them insufficiently stable for an entire HIFU surgery, which can last several hours. We designed and investigated a perfluorocarbon nanodroplet composed of a 1:1 ratio of dodecafluoropentane and decafluorobutane These are tuned to change phase and activate at only 2 MPa peak negative pressure with common HIFU pulse lengths, enabling focused and targeted activation.

Objectives

Methods

Results